Background
Vascularized composite allotransplantation (VCA) can successfully transplant complex donor tissues, such as extremities and facial tissue, to restore full form and long-term functionality Currently, standard preservations strategies for VCA are limited to injury from ischemia, reperfusion and cold static preservation (CSP) We intend to evaluate the ability of suspended animation agents, hydrogen sulfide (H2S) and hydrogen iodide (HI) to prolong CSP of VCA extremities by mitigating injury from reperfusion and hypothermia while maintaining VCA function to improve the function, wellness, and overall quality of life for wounded warriors.
Methods
A total of 62 intact upper extremities from 31 non-human primates (NHP), sourced from other pre-approved protocols in a terminal study, will be procured immediately prior to euthanasia Investigators are blinded to randomization to a control treated University of Wisconsin (UW) solution, UW- H2S treated; or UW- HI treated The venous perfusate of the extremity will be collected and re-perfused through the brachial artery for a total of 5 times, then stored by CSP at 4–8°C for 6,12, and 24 hours After designated CSP duration, warmed and oxygenated allogenic whole blood will be used for reperfusion in a hyperbaric system We will investigate the histological, physiological, genomic, and proteomic consequences of the 3 tissue preservation durations with blood and tissue samples.
Results
54 NHP will be designated to experimental groups, and 6 NHP will be available as needed for cull This is an ongoing study and endpoint results are pending We anticipate our results will be similar to our porcine VCA model, where pre-treatment with H2S to gracilis myocutaneous flaps exposed to 3 hours of CSP, significantly attenuated markers of IRI for up to 2 weeks post-transplant.
Conclusions
Tissue preservation with H2S and HI treated solutions can mitigate both IRI and injury from hypothermia during prolonged preservation If successful, these findings will revolutionize the current clinical practice guidelines for tissue preservation of VCAs.